The present invention relates to a small-sized, thin, magnetic disk drive and, more particularly, to a sealing method therefor.
A magnetic disk drive such as a hard disk drive is constructed such that a magnetic head is allowed to fly over a rotating magnetic disk medium and, with the use of the magnetic head, read and write of data are performed with respect to the magnetic disk medium. Generally, the smaller the flying height between the magnetic head and the magnetic disk medium, the higher the recording density. With the recent demand for increase of capacity or both increase of capacity and reduction of size, the flying height is becoming smaller for the improvement of recording density.
Therefore, it is necessary that a case which houses therein a magnetic disk assembly such as a hard disk assembly (HDA), etc. be partitioned from the exterior lest particles larger than the flying height such as dust suspended within the case should enter the case.
Heretofore, the following methods has been adopted to meet this requirement: a method wherein a clearance between a cover member and a base member both constituting the case is sealed with a gasket or a method wherein the clearance is sealed using a ribbon- or sheet-like sealing member. For example, FIG. 7 shows a magnetic disk drive wherein a clearance between a base member 30 and a cover member 31 both constituting a case is sealed using a ribbon-like sealing member. FIG. 8 is a sectional view taken on line A-A in FIG. 7.
A peripheral edge portion 30a of an opening of the base member 30 is formed so as to be fitted in the cover member 31, whereby the base member 30 is fitted in the cover member 31. A clearance between the base member 30 and the cover member 31 is sealed by winding a ribbon-like sealing member 32 around the outer peripheries of both the base member and the cover member. The outer periphery of the periphery edge portion 30a of the opening is smaller by a width of d than the outer periphery of the bottom of the base member 30 to permit the cover member 31 to be fitted on the base member 30. The magnetic disk drive also includes a width of f of the sealing member 32.
Another case sealing method is shown in FIG. 9. According the method, a flange is formed on the peripheral edge portion of the opening of the base member, a plate-like cover member is disposed so as to cover the opening of the base member, and a sheet-like sealing member 32 is affixed to the cover member to cover the cover member and seal the clearance between the flange and the cover member. Also when this sealing method is used, the height of the magnetic disk drive includes the thickness of the sealing member.